The ancient secret of an olive tree

The Greek island of Santorini is now a picturesque place with beautiful beaches, steep cliffs and blue waters. At one point during the second millennium BC, it was the site of a massive volcanic eruption that blasted ash and rock for many miles around, burying many thriving civilizations in the Mediterranean.

If researchers could tell precisely when this eruption occurred, it would help them to know just how hold these cultures were and how they were connected to other cultures in Egypt and the Near East. Archeologists and scientists have been trying to solve this culture-linking problem for decades, but they haven't been able to agree on an answer.

Now, the remains of a single olive tree have revealed a major clue. Walter Friedrich of the University of Aarhus, in Denmark, and his colleagues discovered the tree in a volcanic rock layer on Santorini.

Because of the way the branches and their bark were preserved, the researchers knew the tree had been buried alive by the eruption. This lucky find gave the researchers a rare opportunity to figure out the age of the eruption, because trees form new rings each year as they grow. So, since the tree was still growing when the volcano exploded, the newest ring would be almost exactly the same age as the eruption.

The researchers used radiocarbon dating to figure out the ages of the tree rings and learned that the eruption took place between 1627 and 1599 BC. This is a century earlier than some archeologists had thought. That means that many of the cultures that researchers once assumed were trading with each other and exchanging ideas, may actually have existed at completely different times.

In particular, researchers have generally thought that the civilizations on the islands of Crete, Cyprus and in Greece had lots of ties to Egypt. But, the new timeline indicates that when these civilizations were going strong, they may have been more tightly linked with cultures from a region called the Levant, which today includes Israel, Palestine, Lebanon and Syria.

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This study is being published in the 28 April 2006 issue of the journal Science.